NBT minifier

[szeweq]

NBT files (from Notch's design) have its data compressed using Gzip. MC-Repack should have a special minifier for checking and recompressing this file format. (Suggestion from #2)

It should use either gzip or zopfli.

[solonovamax]

zopfli can be quite slow based on using it in the past, so idk if it's worth using it tbh

here's a test file I ran through it, with the default zopfli iterations (15):

$ time zopfli --gzip -c infwoodfarm.nbt.uncompressed > infwoodfarm.zopfli.nbt

real	0m10.879s
user	0m10.712s
sys	0m0.032s
$ la
total 1.4M
-rw-r--r-- 1 solonovamax solonovamax  91K May  3 12:44 infwoodfarm.nbt
-rw-r--r-- 1 solonovamax solonovamax 1.2M May  3 12:45 infwoodfarm.nbt.uncompressed
-rw-r--r-- 1 solonovamax solonovamax  68K May  3 12:47 infwoodfarm.zopfli.nbt

so, it saved 24kb in 10 seconds, on a 91kb source file. (note: du shows it as being 92kb originally, so I'm using that)

decreasing it to only 5 iterations still takes 0m8.855s, but results in a file that is 72kb.

reducing it further to 1 iteration takes 0m8.263s, and the result is a file that is (also) 72kb.

Using 20 iterations takes 0m11.375s, and the result is a file that is 68kb, and using 80 iterations takes 0m20.615s, with the result being still 86kb 68kb.

but, if there's like even 20 or so nbt files in a mod, 10 seconds for each is quite long.

[szeweq]

Feature released in v0.20.0. Issue closed.